With every release of a new iPhone powered by another cutting-edge processor designed by Apple, the rumbling grows. It’s amplified by the perception that the Mac is being delayed and hamstrung by the moves of the Mac’s chip supplier, Intel. It’s the theory that, one of these days, Apple is going to break from Intel and power its Macs with an Apple-designed processor related to the ones in the iPhone and iPad.

It’s a story with a certain amount of sense behind it. It seems like several Mac models have been delayed because Intel’s chips just weren’t ready in time, or weren’t ready in enough supply. The latest hubbub about the MacBook Pro being limited to 16GB of RAM is due Apple’s choice of a low-power Intel chipset that couldn’t handle more memory.

And it’s true, the Mac is no stranger to a processor transition. It’s happened three times in the 32-year life of the Mac, so roughly once a decade.

Switching it up

The first was from the Motorola 680x0 series processors that powered the Mac during its first decade of life. In March 1994, Apple switched to the new PowerPC processor architecture created by an alliance of Apple, IBM, and Motorola. Older code compiled for the 680x0 processor series ran in emulation on PowerPC chips.

The second was from PowerPC chips to Intel processors, a transition that was announced in mid–2005 and began in early 2006. Like the previous chip transition, Apple provided emulation technology–this time branded “Rosetta”–that would emulate PowerPC code on Intel Macs.

The Mac Pro was the last Mac to transition to Intel processors in 2006.

Okay, so the 680x0 era lasted 10 years. The PowerPC era lasted 12 years. We’re now almost 11 years into the Intel era. All things being equal, the time seems right for a fourth processor transition, and soon.

It could definitely happen. I don’t want to say that it won’t, because Apple’s desire to chart its own course and not be beholden to other companies for key parts of its products is well known. Having proven itself a capable chip designer with the A series, Apple could very well dump Intel and strike out on its own.

But I don’t think Apple will.

Reasons why Apple would

Beyond simply establishing its independence from Intel, Apple might choose to move the Mac (or some Mac models) to ARM simply because the job of engineering the iPhone has made Apple very, very good at creating powerful, energy-efficient processors. Once you’ve got the skills to design such powerful processors yourself, it isn’t hard to imagine those same people turning their attention to the Mac.

Two-thirds of the Macs Apple sells are laptops. Laptops also need a balance of power and energy efficiency. Presumably an Mac laptop running an Apple-designed chip would follow a similar trajectory, allowing Apple to reduce the size of its battery so it could be even thinner and lighter than today’s models. Or, alternately, the size of today’s models but with more power and battery life.

Reasons why Apple might not

There are lots of arguments against Apple making ARM-based Macs. None of them are deal-breakers, but they all accumulate to suggest that making a break from Intel chips would be a painful transition.

In the past decade, a lot of Mac users have become accustomed to the ability to run Windows in emulation, or use Boot Camp to boot into Windows. Developers can use Windows development environments on their Mac. Game players can reboot and play No Man’s Sky on their iMacs. This is a convenience that would go away should Apple leave Intel behind–or more accurately, it would be a return to a world where running Windows on a Mac was a slow, cumbersome emulated experience.

Adam Patrick Murray

Even an ARM Mac would need more ports than this.

The iPhone and iPad have a single data port: the Lightning port. Macs generally have more complexity. Unless Apple’s only ARM Mac ever was a new version of the MacBook–with its single USB-C port–Apple is going to have to integrate other connection types, including Thunderbolt 3. Right now Apple gets a lot of stuff for free by using Intel’s chipsets, but if it goes its own way it’s going to have to license those technologies and build them itself.

Then there’s the compatibility slog. Older apps will need to be recompiled to run on ARM. Those apps with active developers will probably be fairly easily recompiled, but people use older apps, too. Apple could create an Intel emulator, a la Rosetta, to add compatibility–but at the cost of speed. The Mac has been through this twice before, and it could do it again if it needed to.

The real reason it probably won’t

If the Mac (and the PC market overall) were a thriving, growing business that was a major part of Apple’s future direction, I would probably be ready to beat the drum for a forthcoming ARM transition. And yet… the Mac is less than 15 percent of Apple’s total business, and its sales are relatively flat in an overall PC market that’s contracting.

I don’t mean to sound the alarm bell about the Mac–I think it’s got a good future ahead of it, and I’m one of those people who believes there will be a bunch of new Mac models in 2017, despite the empty year 2016 has been for the Mac.

Apple

Apple probably shouldn't pull engineers off the top-selling iPhone to develop chips for the Mac.

But a processor transition is a major undertaking. It requires a huge engineering effort, both in terms of hardware and software. Mac speeds largely start where iPhone and iPad speeds end; Apple will have to push hard to add even more power to their chip designs to support the higher-end applications of the Mac. And every moment Apple’s chip designers are working on new custom Mac chips is a moment they’re not focused on the next generation of iPhone processors.

The Mac’s great strength is that, unlike iOS, it’s a mature platform with users who are comfortable using computers in the traditional mouse-and-keyboard context. Just as it doesn’t make sense for Apple to turn the Mac into something it’s not (like a tablet), it doesn’t make a lot of sense for Apple to force Mac users through a processor transition. The Mac is the platform of stability and “classic” computing interfaces; iOS is where all the change (and growth) happens.

And that strikes at the heart of it: The Mac will continue to grow and evolve, but it will do so within some very specific constraints. Meanwhile, the iPhone drives the bulk of Apple’s revenues and will do so for the foreseeable future–and that’s Apple’s biggest priority. The Mac gets a lot of benefit from riding along with Intel’s chip developments for personal computers, and it saves Apple from having to divert its attention from iOS in order to invest more resources in a small portion of its business.

Now, watch: Apple will announce an ARM-based MacBook in the spring of 2017. It’s not impossible, not at all. But I’d bet against it. Apple’s got too much riding on the growth and improvement of the iPhone to put its stable platform through an upheaval.

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